Figure 6. Summary of ionic model variable clamps for the single-cell cAF_alt model.

Results for all ionic model variable clamping simulations are summarized in bar graphs showing the percent changes in APD and CaT alternans magnitudes when model variables were clamped to even or odd beat waveforms. Alternans were eliminated (>99% decrease in APD and CaT alternans magnitudes for both even and odd beat waveforms) only when SR release variables were clamped (SR Ca²⁺ release flux, J_SRCarel; RyR open probability, RyR_o; RyR inactivated probability, RyR_i; SR Ca²⁺ ([Ca²⁺]_SR); and junctional Ca²⁺([Ca²⁺]_j). Gating variable f (asterisk) displayed higher order instability when clamping to the even beat waveform, so the increase in alternans magnitude was considered infinitely large. Left column: SR fluxes and sarcolemmal currents. Right column: state variables.